Cell Organelles and Structures

Vocabulary flashcards defining cellular organelles and their functions based on the lecture material.

Golgi body

Modifies, stores, sorts, and ships molecules. Looks a bit like a stack of hollow pancakes. A membranous organelle.

Rough Endoplasmic Reticulum

Newly synthesized proteins are folded here (tertiary and quaternary structure). Proteins may also be modified here and then shipped to the Golgi. A membranous organelle.

Smooth Endoplasmic Reticulum

Synthesizes phospholipids and cholesterol for plasma membranes in addition to other lipids. Capable of sequestering calcium in muscle cells and glycogen in liver cells.

Nucleus

A large, membranous organelle that contains the cell's DNA and regulates cellular activity. Can be seen under the light microscope.

Nucleolus

A transient organelle that is found inside the nucleus (watch the spelling!) and is where ribosomes are produced in two parts so they can exit through a nuclear pore.

Ribosome

A non-membranous organelle that is the site of protein synthesis. This organelles assembles amino acids into polypeptides (primary structure of protein). Some are free in the cytoplasm and some are fixed to the RER.

Lysosome

A membranous organelle that can break down organic molecules and damaged organelles or pathogens. Contain lysozyme (a hydrolytic enzyme).

Peroxisome

A membranous organelle where organic molecules can be broken down and toxic compounds such as hydrogen peroxide can be neutralized.

Vesicle

A membranous organelle used for transport around the cell. Also may be involved in exocytosis and endocytosis.

Nuclear Envelope/ Membrane

A double membrane that surrounds the nucleus. It protects the DNA/Chromosomes contained inside and heavily regulates what can move in and out of the nucleus.

Microtubule

Found in cytoplasm radiating away from the centrosome. Give the cell strength and help move organelles. Essential in spindle formation during mitosis to move chromosomes.

Centriole

Part of the cytoskeleton (non-membranous organelles), these are cylindrical structures made of microtubules located inside a centrosome. Play a critical role in mitosis. Cells without centrioles cannot divide.

Mitochondrion

A double-membrane organelle that produces ATP in the presence of oxygen to meet the energy demands of the cell. Key feature is the cristae which increase surface area for enzymes.

Cytoplasm

Includes both cytosol (the liquid part) and the organelles of the cell.

Cell Membrane

A bilipid layer composed of phospholipids, cholesterol, and proteins that is semi-permeable and separates the cell from the external environment.

Nuclear Pore

Passageways in the nuclear envelope that allow for communication and the movement of some molecules in or out of the nucleus. DNA cannot exit through the pores under normal conditions.

Cytoskeleton

A protein network that serves as the cell's skeleton. It includes microfilaments, intermediate filaments, and microtubules. Associated with microvilli, cilia, and flagella.

Microvilli

Part of the cytoskeleton, these structures are extensions of the cell membrane and increase the surface area of the cell for absorption.